Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/475—Preparation of carboxylic acid esters by splitting of carbon-to-carbon bonds and redistribution, e.g. disproportionation or migration of groups between different molecules
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/28—Preparation of carboxylic acid esters by modifying the hydroxylic moiety of the ester, such modification not being an introduction of an ester group
  • C07C67/293—Preparation of carboxylic acid esters by modifying the hydroxylic moiety of the ester, such modification not being an introduction of an ester group by isomerisation; by change of size of the carbon skeleton

Definitions

• the present invention relates to a process for the metathesis of alkenyl esters utilizing a homogeneous catalyst comprised of tungsten hexachloride and a tetraalkyltin.
• Chem., 218, 69-80 (1981)) have metathesized oleyl acetate to obtain 9-octadecene and 1,18-diacetoxy-9-octadecene using WCl 6 or WOCl 4 as the primary catalyst with SnMe 4 , Cp 2 TiMe 2 or Cp 2 TiClMe as co-catalyst.
• 4-acetoxy-1-butane, 5-acetoxy-1-pentene and 6-acetoxy-1-hexene were cross metathesized with 2-hexene and cyclooctene using WCl 6 /Sn(Me) 4 catalyst by Otton et al., (J. Mol.
• the process of this invention involves contacting an alkenyl ester, alone or in combination with an alkene, with a tungsten hexachloride/tetraalkyltin catalyst at a temperature from 0° C. to 200° C., said tungsten hexachloride present in an amount from 0.1 to 5 mole percent, based on the alkenyl ester, and the molar ratio of tetraalkyltin to tungsten hexachloride ranging from 0.4:1 to 6:1.
• a nitrogeneous or trivalent phosphorous modifying agent may be employed with the tungsten hexachloride and tetraalkyltin at a mole ratio (modifier:WCl 6 ) of 0.01:1 to 0.75:1.
• Alkenyl esters employed for the process have the formula ##STR2## where R is hydrogen or an alkyl group having from 1 to 10 carbon atoms, n is an integer from 2 to 20 and R* is
• alkenyl esters have from 4 to 22 carbon atoms in the alkenyl moiety with R* being a tertiary alkyl group containing from 4 to 9 carbon atoms or an aromatic moiety where R 5 is hydrogen and R 4 is hydrogen, chloro, bromo, or a C 1-4 alkyl group.
• Alkenes which can be present with the alkenyl ester contain from 3 to 50 carbon atoms and correspond to the formula ##STR5## where R' is an alkyl group having from 1 to 40 carbon atoms, a C 3-6 cycloalkyl alkyl-substituted cycloalkyl having from 4 to 20 carbon atoms, phenyl or alkyl-substituted phenyl having from 7 to 20 carbon atoms or a radical of the formula ##STR6## where X is an integer from 1 to 20, R", R'" and R"" are hydrogen or a radical as defined for R'.
• ⁇ -Olefins are especially useful alkenes.
• an ⁇ -alkenyl ester wherein R is hydrogen and n is an integer from 6 to 16 is reacted at a temperature of 50° C. to 150° C. utilizing 0.25 to 3 mole percent tungsten hexachloride. It is even more preferable if the reaction is carried out using a (C 1-4 alkyl) 4 Sn compound and pyridine modifier.
• alkenyl ester is metathesized utilizing a homogeneous catalyst comprised of tungsten hexachloride and a tetraalkyltin compound.
• Alkenyl esters employed for the metathesis correspond to the general formula ##STR7## where R is hydrogen or an alkyl group having from 1 to 10 carbon atoms, n is an integer from 2 to 20 and R* is
• the total number of carbon atoms in the alkenyl moiety RHC ⁇ CH 2 (CH 2 ) n -- is from 4 to 22 and, in a particularly useful embodiment of this invention, the alkenyl group is an ⁇ -alkenyl radical, i.e., R ⁇ H, with n being an integer from about 6 to 16.
• the tertiary alkyl group (a) preferably contains from 4 to 9 carbon atoms and it is particularly advantageous if R 1 , R 2 and R 3 are methyl groups.
• Preferred phenyl or substituted-phenyl radicals (b) have R 4 ⁇ H, chloro, bromo or C 1-4 alkyl and R 5 ⁇ H.
• alkenyl esters are readily obtained by the reaction of an unsaturated alcohol of the formula RHC ⁇ CH 2 (CH 2 ) n OH with a neo-acid of the formula ##STR10## or aromatic acid of the formula ##STR11## where R, R 1 , R 2 , R 3 , R 4 , R 5 and n are the same as defined above.
• Neo-acids which can be reacted with the above-defined unsaturated alcohols include 2,2-dimethylpropanoic acid (trimethylacetic acid; pivalic acid, neo-pentanoic acid), 2,2-dimethylbutanoic acid, 2,2-dimethylpentanoic acid, 2,2-dimethylheptanoic acid, 4-ethyl-2,2-dimethyloctanoic acid, 2,2-dimethyldecanoic acid, commercially available acids which PG,8 consist primarily of C 10 tertiary acids or mixtures of C 9-11 tertiary acids, and the like.
• Aromatic acids which can be employed to obtain the alkenyl esters used in the process include, most notably, benzoic acid, 2-, 3- or 4-chlorobenzoic acid, 2- , 3- or 4-bromobenzoic acid, 2,4-dibromobenzoic acid, 2,6-dichlorobenzoic acid, 4-methylbenzoic acid, 4-ethylbenzoic acid, 4-t-butylbenzoic acid, 2,4-dimethylbenzoic acid, 2,6-dimethylbenzoic acid, and the like.
• Esters of tri- and higher-substituted benzoic acids may also be employed.
• Alkenes useful for co-metathesis with the alkenyl esters include olefinic hydrocarbons having from 3 up to about 50 carbon atoms and corresponding to the general formula ##STR13## where R' is an alkyl group having from 1 to 40 carbon atoms, C 3-6 cycloalkyl or alkyl-substituted cycloalkyl having from 4 to 20 carbon atoms, phenyl or alkyl-substituted phenyl having from 7 to 20 carbon atoms or radical of the formula ##STR14## where x is an integer from 1 to 20, and R", R'" and R"" are, independently, hydrogen or a radical as defined above for R'.
• a pure olefin may be employed or a mixture of olefins, which can be the same or different types, can be utilized.
• cyclic olefins such as cyclohexene and cyclooctene can be employed.
• ⁇ -Olefins where R", R'" and R"" are hydrogen and R' is an alkyl group having from 1 to 30 and, more preferably, 4 to 16, carbon atoms are particularly advantageous for cross-metathesis with the alkenyl esters.
• Suitable ⁇ -olefins include, but are not limited to, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene and the like.
• the co-metathesis reaction is represented by the equation ##STR15## where R*, R' and n are the same as defined above. It is possible to obtain a variety of useful products by such reactions.
• an 11-dodecenyl ester can be cross-metathesized with 1-eicosene to yield as the principle component an 11-triacontenyl ester which, after separation from the other components, can be hydrolyzed and reduced to obtain 1-triacontanol, a known growth promoter.
• Tungsten hexachloride is employed as the catalyst in conjunction with a tetraalkyltin compound. for the metathesis and co-metathesis reactions. While small amounts of tungsten oxyhalides may be present with the tungsten hexachloride, it is preferable to keep the level of tungsten oxy-compounds to as low a level as possible for optimum results. For this reason, it is sometimes advantageous to purify the tungsten hexachloride prior to use. This is readily accomplished by heating the tungsten hexachloride at 200° C. under a constant flow of nitrogen for about two hours.
• Tetraalkyltin compounds useful as co-catalytic agents with the tungsten hexachloride have the general formula ##STR16## where R 6 , R 7 , R 8 and R 9 are, independently, an alkyl group containing from 1 to 12 carbon atoms. Tetraalkyltin compounds of the above type include tetramethyltin, dimethyldiethyltin, tetraethyltin, diethyldibutyltin, tetrabutyltin, tetraoctyltin, and the like.
• tetraalkyltin compounds wherein the alkyl groups (R 6 , R 7 , R 8 and R 9 ) contain from 1 to 4 carbon atoms.
• Organotin compounds wherein one or more of the alkyl groups is replaced with a cycloalkyl, phenyl or alkyl-substituted phenyl and benzyl or alkyl-substituted benzyl group may also be used as a co-catalyst with the tungsten hexachloride.
• the molar ratio of the tetraalkyltin compound to tungsten hexachloride can range from about 0.4:1 to 6:1, however, catalyst systems wherein the molar ratio is 1:1 to 4:1 are particularly advantageous.
• Known nitrogeneous and trivalent phosphorous modifying agents can also be present with the tungsten hexachloride and tetraalkyltin compound. While such modifying agents are not necessary for the process, they can be advantageous depending on the particular reactants and reaction conditions employed.
• a modifier When a modifier is employed, it will generally be present at a mole ratio of 0.01:1 to 0.75:1 (modifier:WCl 6 ).
• pyridine is used as the modifier at a molar ratio (pyridine:WCl 6 ) of 0.1:1 to 0.5:1.
• the process can be conducted over a wide range of temperatures from about 0° C. up to about 220° C. but, most generally, the reaction temperature will range from 50° C. to 150° C.
• Operating pressures can vary from sub-atmospheric to super-atmospheric and the pressure will generally be governed by the reactants and other operating conditions. Whenever possible, the reaction is conducted at atmospheric pressure or as close thereto as possible. An inert atmosphere of nitrogen, argon or helium is generally employed and precautions are taken to exclude moisture from the system.
• an inert hydrocarbon diluent such as benzene, toluene, xylene, cyclohexane, methylcyclohexane, pentane, hexane, isooctane, or other inert aromatic, paraffinic or cycloparaffinic hydrocarbons can be employed.
• the tungsten hexachloride is combined with the alkenyl ester and the mixture heated to the desired temperature under a nitrogen atmosphere. After stirring for a short period of time, the tetraalkyltin compound and any modifying agent is charged to the reactor. If an ⁇ -alkenyl ester is employed, evolution of ethylene occurs almost immediately. While equilibrium is generally reached after about only 15 minutes (as determined by the amount of ethylene evolved), the reaction is continued for a total of about two hours. The reaction mixture is then filtered through a suitable filtering medium and the metathesis product recovered.
• Freshly sublimed tungsten hexachloride (0.59 gram; 1.5 mmole) was weighed into a dry glass reactor under an atmosphere of nitrogen and 38.1 grams (0.15 mole) 10-undecenyl pivalate added (mole ratio 10-undecenyl pivalate to WCl 6 of 100:1).
• the solution was heated to 90° C. under nitrogen with stirring and 1.56 grams (4.5 mmole) tetrabutyltin added (mole ratio tetrabutyltin to WCl 6 of 3:1). Evolution of ethylene was observed almost immediately. Heating and stirring were continued for two hours--after which time ethylene evolution was no longer evident.
• the reaction mixture was then filtered through a diatomaceous earth filter bed.
• Example I The procedure of Example I was identically repeated except that the reaction was carried out at a temperature of 120° C.
• the conversion of 10-undecenyl pivalate was 68.7 percent with 86.7 percent selectivity to the desired 1,20-dipivaloxy-10-eicosene.
• 10-Undecenyl benzoate was metathesized as follows: 0.40 Gram (1.0 mmole) tungsten hexachloride was charged to the reactor with 37.44 grams (0.1366 mole) 10-undecenyl benzoate (mole ratio 10-undecenyl benzoate to WCl 6 of 136.6:1). The solution was stirred and heated under a nitrogen atmosphere to 90° C. and 0.02 gram pyridine added. After five minutes, tetrabutyltin (1.04 grams; 3.0 mmole) was added. After two hours, 44.1 percent conversion of the 10-undecenyl benzoate was obtained with 85.7 percent selectivity to the desired 1,20-dibenzooxy-10-eicosene.
• Example X was repeated except that the amount of tungsten hexachloride was reduced even further (mole ratio 10-undecenyl benzoate:tungsten hexachloride 410:1). After two hours of reaction at 90° C., 16.1 percent conversion of the 10-undecenyl benzoate was obtained. By additional reaction it was possible to increase the conversion of the 10-undecenyl benzoate. Selectivity of the reaction to the desired 1,20-dibenzooxy-10-eicosene was 80 percent.
• 10-undecenyl para-t-butylbenzoate (33.1 grams) was metathesized by heating at 90° C. in the presence of 0.40 gram tungsten hexachloride, 1.04 grams tetrabutyltin and 0.02 gram pyridine. After two hours, 56.5 percent conversion of the 10-undecenyl para-t-butylbenzoate was obtained with 91 percent selectivity to the desired diester product, 1,20-bis(para-t-butylbenzooxy)-10-eicosene.
• reaction A 10-undecenyl pivalate was used and for the second, reaction B, the alkenyl ester was 10-undecenyl benzoate.
• reaction B the alkenyl ester was 10-undecenyl benzoate.
• reaction C was conducted using 10-undecenyl acetate, an ester used in the prior art for metathesis reactions.
• Example XV was repeated except that pyridine was employed as a modifier with the tungsten hexachloride and tetrabutyltin.
• the pyridine (0.04 gram) was added after introduction of the tungsten hexachloride (0.79 gram) and after the temperature of the solution was 130° C.
• the mole ratio of 10-undecenyl pivalate to tungsten hexachloride was 200:1.
• the mixture was then allowed to stir for five minutes before the tetrabutyltin (2.08 grams) was charged. 75.1 Percent conversion was obtained after two hours with a selectivity of 81.2 percent.
• the product distribution was essentially the same as obtained without the pyridine modifier.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Polyoxymethylene Polymers And Polymers With Carbon-To-Carbon Bonds (AREA)

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• 1983
  • 1983-10-13 US US06/541,757 patent/US4496758A/en not_active Expired - Fee Related
• 1984
  • 1984-09-27 CA CA000464206A patent/CA1232612A/en not_active Expired
  • 1984-10-03 MX MX202935A patent/MX156294A/es unknown
  • 1984-10-09 AU AU34058/84A patent/AU566216B2/en not_active Ceased
  • 1984-10-10 DE DE8484112154T patent/DE3480702D1/de not_active Expired - Lifetime
  • 1984-10-10 EP EP84112154A patent/EP0137493B1/de not_active Expired
  • 1984-10-10 BR BR8405114A patent/BR8405114A/pt unknown
  • 1984-10-12 JP JP59212807A patent/JPS6097930A/ja active Pending
  • 1984-10-12 NZ NZ209872A patent/NZ209872A/en unknown
  • 1984-10-12 IE IE2609/84A patent/IE57637B1/en not_active IP Right Cessation

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